1. Field of the Invention
The present invention relates to electron beam (e-beam) apparatus and metrology.
2. Description of the Background Art
As technology progresses in the semiconductor industry, the features of integrated circuit devices are being reduced to smaller and smaller sizes. Such reduction in feature size enables a greater density of devices to be manufactured on a semiconductor. However, increasingly smaller feature sizes require increasingly higher resolutions and accuracy in measurement, inspection, and review equipment.
One category of such equipment is based on scanning electron microscope (SEM) technology. In an SEM, a beam of electrons (an electron beam or e-beam) is scanned over a specimen, and the resulting electrons that are returned from the specimen surface are used to create an image of the specimen surface. In order to handle increasingly smaller feature sizes, it is desirable to increase the effective accuracy of SEM-based equipment used for feature measurement, substrate inspection, or defect review.